My DD ate everything in sight for quite awhile. Basically I'd try to be ready with some sort of finger food when she was playing with something with "eating potential" and every time I saw her putting the nonedible in her mouth I would try to shove a cheerio or something in there and say something like "We only eat food, leaves aren't food," or something to that effect. I'd also make a big deal out of it if she handed me something she wasn't supposed to be eating when I could see it was on her way to her mouth. (Of course now at 20 months I have a child that doesn't eat things she's not supposed to, but does obsessively pick dirt up off the floor and hand it to me LOL!)